Dielectric Properties of Triglycine Sulphate Crystals Admixtured with Phosphoric Acid

Abstract

Triglycine sulphate crystals admixtured with phosphoric acid were studied. The crystals were grown from a solution containing 50% of phosphoric acid, by a dynamic method at a constant temperature, below and above the Curie point, by slow evaporation of water. The temperature dependencies of permittivity ϵ′ and loss tangent tgδ were determined at different frequencies of the measuring field, from 0.1 to 13000 kHz. For some of the samples cut out of the crystals grown below the Curie point, two maxima of ϵ′(T) and tgδ (T) and unipolar hysteresis loops were observed, which indicated the occurrence of the bias field E_b. For the crystals grown above the Curie point, only single maxima of ϵ′ (T) and tgδ (T) were observed and the unipolar hysteresis loops did not occur.

Keywords:

• Triglycerine sulphate
• dielectric properties